Structural insights into ABC transporter mechanism.
ATP-binding cassette (ABC) transporters utilize the energy from ATP hydrolysis to transport substances across the membrane. In recent years, crystal structures of several ABC transporters have become available. These structures show that both importers and exporters oscillate between two conformations: an inward-facing conformation with the substrate translocation pathway open to the cytoplasm and an outward-facing conformation with the translocation pathway facing the opposite side of the membrane. In this review, conformational differences found in the structures of homologous ABC transporters are analyzed to understand how alternating-access is achieved. It appears that rigid-body rotations of the transmembrane subunits, coinciding with the opening and closing of the nucleotide-binding subunits, couples ATP hydrolysis to substrate translocation.
Oldham
Michael L
ML
Department of Biological Sciences, Purdue University, 915 W. State Street, West Lafayette, IN 47907, USA. mloldham@purdue.edu
Davidson
Amy L
AL
Chen
Jue
J
D018528:ATP-Binding Cassette Transporters / Q000737:chemistry* / Q000378:metabolism*; D000818:Animals; D001665:Binding Sites; D003461:Crystallography; D026901:Membrane Transport Proteins / Q000737:chemistry / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D017434:Protein Structure, Tertiary
D018528:ATP-Binding Cassette Transporters; D026901:Membrane Transport Proteins